Glucose-fructose oxidoreductase (GFOR) catalyses the formation of D-gluconolactone and D-glucitol from D-glucose and D-fructose. It hasone tightly-bound NADP(H) per enzyme subunit, it exists as a homotetramer,and is one of the pivotal proteins in the sorbitol-gluconate pathway.It istargeted to the periplasm of the Gram-negative cell envelope, and belongs tothe GFO/IDH/MOCA superfamily. First discovered in Zymomonas mobilis, homologues have also been found in Caulobacter crescentusand Deinococcus radiodurans.GFOR is of great interest as its mechanism of secretion into the bacterialperiplasm differs from other precursor proteins of the Twin ArginineTranslocation (TAT) pathway []. Although it exhibits the consensus TAT signal motif (S/T-R-R-x-L-F-K) at its N terminus, unlike other TAT proteins that can be universally secreted across a number of Gram-negative microbes, GFOR is only translocated in Z. mobilis. However, replacing the Z. mobilis signal peptide with one from Escherichia colirestores this function. This observation has led to the suggestion that TAT-dependent precursors are optimally adapted only to their particular cognate secretion apparatus [].Recently, the crystal structure of Z. mobilis GFOR was resolved to 2.5A bymeans of X-ray crystallography. This revealed that the protein indeed exists as a homotetramer, and has 4 active sites. There are 2 distinct domains: a classical dinucleotide binding fold at the N terminus and a 9-stranded beta-sheet at the C terminus. NADP(H) is bound to the N terminus of the first alpha-helix.

This database is part of a project that received funding from the European Research Council (ERC) under the European Union's Horizon 2020 research and innovation programme (grant agreement number 649024).